@ossobuco,
That's the Plaza Mayor I remember.
Yes, I did visit the Prado. I also remember a painting of a huge living room that has several young girls in it. I don't remember the name of that painting, but I can still picture it in my mind's eye.
I know I had my picture taken by the Prado, and it's driving me nuts, because I can't seem to locate it. I also should have a picture of Plaza Major, and the main street in Madrid where the main post office is located.